A method, apparatus and computer program product for use in identifying and blocking operation of compromised or potentially compromised IoT device(s) on a network, such as a local network behind a router or firewall. To this end, the technique provides for automated and seamless on-boarding of a “guard” system for IoT devices, preferably as those devices join (or re-join) into the network via a Dynamic Host Configuration Protocol message exchange. In operation, and in response to receipt of a DHCP discover message that includes a network location, a DHCP server uses the network location to locate and retrieve a set of flow attributes for the device. Those attributes are then associated with the IP address to be assigned to the IoT device in a network control device. The network control device then selectively identifies and/or blocks operation of the IoT device when the IoT device is compromised or potentially compromised, thereby protecting the network (or network resources) from damage or misuse.